In recent years, surgical staples have come into wide use as an alternative to sutures in closing incisions of skin, fascia, and internal organs. Staples have an advantage over sutures in some applications due to the speed and ease with which staples may be placed. In addition, special stapling instruments have been designed which place an entire row or ring of staples in a single operation to further simplify and speed up the surgical procedure.
Surgical staples currently in use are fabricated of tantalum or stainless steel wire having sufficient tensile strength and bending modules to assure that the staple will remain closed after it has been set in place. Although it has long been recognized that the staples made of plastic or polymeric materials would be desirable for use in surgical applications, the development of such staples has been difficult due to inherent resiliency of such materials. Staples of known plastic compositions and of the same configuration as a metallic staple do not have sufficient strength and bending modulus to stay closed after being set in place. One approach to utilizing plastic materials in surgical stapling procedures has been to provide cooperating mechanical means to secure the staple in its set configuration. U.S. Pat. No. 2,881,762 proposed a circular, open ring-type staple wherein the ends were designed to pierce the tissue, overlap and lock to form a closed ring through the tissue similar to a knotted suture. More recently, a two-piece staple was suggested in U.S. Pat. No. 4,060,089 wherein a pronged fastener strip pierced the tissue and a cooperating retainer strip gripped the prongs on the opposite side of the tissue. This device is limited in its application to situations where access to both sides of the tissue is available, and a special tool is required to apply the device.
It is an object of the present invention to provide a plastic staple which functions in a manner analagous to that of a metallic staple, i.e., a one-piece device which is applied from one side of the tissue. It is a further object of the present invention to provide a plastic staple which can be set with a tool of conventional design. It is yet a further object of the present invention to provide plastic staples fabricated of biologically absorbable polymers as well as of conventional nonabsorbable polymers. These and other objects of the present invention will be apparent from the ensuing description and claims.